The Antioxidant, Anti-inflammatory, and Anti-angiogenic Effects of Fucoxanthin on Corneal Structural and Biochemical Changes of Streptozotocin-induced Diabetes in Rats

Abstract Background: Diabetes mellitus is a worldwide disease with different endocrine and metabolic disorders due to hyperglycemia. Diabetic corneal complications affect more than 70% of diabetics. Fucoxanthin (FX) is a carotenoid that possesses antioxidant, anti-inflammatory, anti-angiogenic, and anti-diabetic effects. Materials and Methods: A total of 35 Wistar rats weighted 140–160 g of 12–14 weeks were divided into control; streptozotocin (STZ): rats received a single dose (50 mg/kg) of STZ intraperitoneally; STZ + FX low dose; STZ + FX intermediate dose; and STZ + FX high dose: diabetic rats treated with FX 100, 200, and 400 mg/kg, respectively, orally by an intragastric tube daily for 3 weeks. Then, blood and eye samples were managed for biochemical, histological, and immunohistochemical evaluations. Results: The STZ group revealed an increase in blood glucose level, plasma glycosylated hemoglobin A1c% significantly, and serum total cholesterol and low-density lipoprotein, malondialdehyde tissue levels, significantly reduced serum high-density lipoprotein, tissue superoxide dismutase, and reduced glutathione levels. In addition, severe corneal injury is seen by hematoxylin & eosin with deeply stained epithelial cell nuclei, and cytoplasm vacuolation, besides Bowman’s membrane irregularities. Additionally, stromal widely separated collagen fibers, mononuclear cellular infiltrations, stromal vascularization, and swollen endothelial cells were seen. In addition, marked thickening of Bowman’s and Descemet’s membranes was demonstrated by periodic acid Schiff. In addition, E-cadherin diffuse cytoplasmic reaction, significantly increased immunohistochemical expression and optical density of interleukin-1β, metalloproteinase-3, and vascular endothelial growth factor, whereas significantly reduced the optical density of epidermal growth factor. The STZ-treated groups with different doses of FX showed dose-dependent improvement of the previously documented findings. Conclusion: FX ameliorates STZ-induced corneal changes in a dose-dependent manner in rats through its antioxidant, anti-inflammatory, anti-angiogenic, and anti-diabetic actions.